libcxxrt

exception.cc (47652B)

---

 /* 
  * Copyright 2010-2011 PathScale, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright notice,
  *    this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright notice,
  *    this list of conditions and the following disclaimer in the documentation
  *    and/or other materials provided with the distribution.
  * 
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
  * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <stdlib.h>
 #include <dlfcn.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdint.h>
 #include <pthread.h>
 #include "typeinfo.h"
 #include "dwarf_eh.h"
 #include "atomic.h"
 #include "cxxabi.h"
 
 #pragma weak pthread_key_create
 #pragma weak pthread_setspecific
 #pragma weak pthread_getspecific
 #pragma weak pthread_once
 #ifdef LIBCXXRT_WEAK_LOCKS
 #pragma weak pthread_mutex_lock
 #define pthread_mutex_lock(mtx) do {\
 	if (pthread_mutex_lock) pthread_mutex_lock(mtx);\
 	} while(0)
 #pragma weak pthread_mutex_unlock
 #define pthread_mutex_unlock(mtx) do {\
 	if (pthread_mutex_unlock) pthread_mutex_unlock(mtx);\
 	} while(0)
 #pragma weak pthread_cond_signal
 #define pthread_cond_signal(cv) do {\
 	if (pthread_cond_signal) pthread_cond_signal(cv);\
 	} while(0)
 #pragma weak pthread_cond_wait
 #define pthread_cond_wait(cv, mtx) do {\
 	if (pthread_cond_wait) pthread_cond_wait(cv, mtx);\
 	} while(0)
 #endif
 
 using namespace ABI_NAMESPACE;
 
 /**
  * Saves the result of the landing pad that we have found.  For ARM, this is
  * stored in the generic unwind structure, while on other platforms it is
  * stored in the C++ exception.
  */
 static void saveLandingPad(struct _Unwind_Context *context,
                            struct _Unwind_Exception *ucb,
                            struct __cxa_exception *ex,
                            int selector,
                            dw_eh_ptr_t landingPad)
 {
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 	// On ARM, we store the saved exception in the generic part of the structure
 	ucb->barrier_cache.sp = _Unwind_GetGR(context, 13);
 	ucb->barrier_cache.bitpattern[1] = static_cast<uint32_t>(selector);
 	ucb->barrier_cache.bitpattern[3] = reinterpret_cast<uint32_t>(landingPad);
 #endif
 	// Cache the results for the phase 2 unwind, if we found a handler
 	// and this is not a foreign exception.  
 	if (ex)
 	{
 		ex->handlerSwitchValue = selector;
 		ex->catchTemp = landingPad;
 	}
 }
 
 /**
  * Loads the saved landing pad.  Returns 1 on success, 0 on failure.
  */
 static int loadLandingPad(struct _Unwind_Context *context,
                           struct _Unwind_Exception *ucb,
                           struct __cxa_exception *ex,
                           unsigned long *selector,
                           dw_eh_ptr_t *landingPad)
 {
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 	*selector = ucb->barrier_cache.bitpattern[1];
 	*landingPad = reinterpret_cast<dw_eh_ptr_t>(ucb->barrier_cache.bitpattern[3]);
 	return 1;
 #else
 	if (ex)
 	{
 		*selector = ex->handlerSwitchValue;
 		*landingPad = reinterpret_cast<dw_eh_ptr_t>(ex->catchTemp);
 		return 0;
 	}
 	return 0;
 #endif
 }
 
 static inline _Unwind_Reason_Code continueUnwinding(struct _Unwind_Exception *ex,
                                                     struct _Unwind_Context *context)
 {
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 	if (__gnu_unwind_frame(ex, context) != _URC_OK) { return _URC_FAILURE; }
 #endif
 	return _URC_CONTINUE_UNWIND;
 }
 
 
 extern "C" void __cxa_free_exception(void *thrown_exception);
 extern "C" void __cxa_free_dependent_exception(void *thrown_exception);
 extern "C" void* __dynamic_cast(const void *sub,
                                 const __class_type_info *src,
                                 const __class_type_info *dst,
                                 ptrdiff_t src2dst_offset);
 
 /**
  * The type of a handler that has been found.
  */
 typedef enum
 {
 	/** No handler. */
 	handler_none,
 	/**
 	 * A cleanup - the exception will propagate through this frame, but code
 	 * must be run when this happens.
 	 */
 	handler_cleanup,
 	/**
 	 * A catch statement.  The exception will not propagate past this frame
 	 * (without an explicit rethrow).
 	 */
 	handler_catch
 } handler_type;
 
 /**
  * Per-thread info required by the runtime.  We store a single structure
  * pointer in thread-local storage, because this tends to be a scarce resource
  * and it's impolite to steal all of it and not leave any for the rest of the
  * program.
  *
  * Instances of this structure are allocated lazily - at most one per thread -
  * and are destroyed on thread termination.
  */
 struct __cxa_thread_info
 {
 	/** The termination handler for this thread. */
 	terminate_handler terminateHandler;
 	/** The unexpected exception handler for this thread. */
 	unexpected_handler unexpectedHandler;
 	/**
 	 * The number of emergency buffers held by this thread.  This is 0 in
 	 * normal operation - the emergency buffers are only used when malloc()
 	 * fails to return memory for allocating an exception.  Threads are not
 	 * permitted to hold more than 4 emergency buffers (as per recommendation
 	 * in ABI spec [3.3.1]).
 	 */
 	int emergencyBuffersHeld;
 	/**
 	 * The exception currently running in a cleanup.
 	 */
 	_Unwind_Exception *currentCleanup;
 	/**
 	 * Our state with respect to foreign exceptions.  Usually none, set to
 	 * caught if we have just caught an exception and rethrown if we are
 	 * rethrowing it.
 	 */
 	enum 
 	{
 		none,
 		caught,
 		rethrown
 	} foreign_exception_state;
 	/**
 	 * The public part of this structure, accessible from outside of this
 	 * module.
 	 */
 	__cxa_eh_globals globals;
 };
 /**
  * Dependent exception.  This 
  */
 struct __cxa_dependent_exception
 {
 #if __LP64__
 	void *primaryException;
 #endif
 	std::type_info *exceptionType;
 	void (*exceptionDestructor) (void *); 
 	unexpected_handler unexpectedHandler;
 	terminate_handler terminateHandler;
 	__cxa_exception *nextException;
 	int handlerCount;
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 	_Unwind_Exception *nextCleanup;
 	int cleanupCount;
 #endif
 	int handlerSwitchValue;
 	const char *actionRecord;
 	const char *languageSpecificData;
 	void *catchTemp;
 	void *adjustedPtr;
 #if !__LP64__
 	void *primaryException;
 #endif
 	_Unwind_Exception unwindHeader;
 };
 
 
 namespace std
 {
 	void unexpected();
 	class exception
 	{
 		public:
 			virtual ~exception() throw();
 			virtual const char* what() const throw();
 	};
 
 }
 
 /**
  * Class of exceptions to distinguish between this and other exception types.
  *
  * The first four characters are the vendor ID.  Currently, we use GNUC,
  * because we aim for ABI-compatibility with the GNU implementation, and
  * various checks may test for equality of the class, which is incorrect.
  */
 static const uint64_t exception_class =
 	EXCEPTION_CLASS('G', 'N', 'U', 'C', 'C', '+', '+', '\0');
 /**
  * Class used for dependent exceptions.  
  */
 static const uint64_t dependent_exception_class =
 	EXCEPTION_CLASS('G', 'N', 'U', 'C', 'C', '+', '+', '\x01');
 /**
  * The low four bytes of the exception class, indicating that we conform to the
  * Itanium C++ ABI.  This is currently unused, but should be used in the future
  * if we change our exception class, to allow this library and libsupc++ to be
  * linked to the same executable and both to interoperate.
  */
 static const uint32_t abi_exception_class = 
 	GENERIC_EXCEPTION_CLASS('C', '+', '+', '\0');
 
 static bool isCXXException(uint64_t cls)
 {
 	return (cls == exception_class) || (cls == dependent_exception_class);
 }
 
 static bool isDependentException(uint64_t cls)
 {
 	return cls == dependent_exception_class;
 }
 
 static __cxa_exception *exceptionFromPointer(void *ex)
 {
 	return reinterpret_cast<__cxa_exception*>(static_cast<char*>(ex) -
 			offsetof(struct __cxa_exception, unwindHeader));
 }
 static __cxa_exception *realExceptionFromException(__cxa_exception *ex)
 {
 	if (!isDependentException(ex->unwindHeader.exception_class)) { return ex; }
 	return reinterpret_cast<__cxa_exception*>((reinterpret_cast<__cxa_dependent_exception*>(ex))->primaryException)-1;
 }
 
 
 namespace std
 {
 	// Forward declaration of standard library terminate() function used to
 	// abort execution.
 	void terminate(void);
 }
 
 using namespace ABI_NAMESPACE;
 
 
 
 /** The global termination handler. */
 static terminate_handler terminateHandler = abort;
 /** The global unexpected exception handler. */
 static unexpected_handler unexpectedHandler = std::terminate;
 
 /** Key used for thread-local data. */
 static pthread_key_t eh_key;
 
 
 /**
  * Cleanup function, allowing foreign exception handlers to correctly destroy
  * this exception if they catch it.
  */
 static void exception_cleanup(_Unwind_Reason_Code reason, 
                               struct _Unwind_Exception *ex)
 {
 	// Exception layout:
 	// [__cxa_exception [_Unwind_Exception]] [exception object]
 	//
 	// __cxa_free_exception expects a pointer to the exception object
 	__cxa_free_exception(static_cast<void*>(ex + 1));
 }
 static void dependent_exception_cleanup(_Unwind_Reason_Code reason, 
                               struct _Unwind_Exception *ex)
 {
 
 	__cxa_free_dependent_exception(static_cast<void*>(ex + 1));
 }
 
 /**
  * Recursively walk a list of exceptions and delete them all in post-order.
  */
 static void free_exception_list(__cxa_exception *ex)
 {
 	if (0 != ex->nextException)
 	{
 		free_exception_list(ex->nextException);
 	}
 	// __cxa_free_exception() expects to be passed the thrown object, which
 	// immediately follows the exception, not the exception itself
 	__cxa_free_exception(ex+1);
 }
 
 /**
  * Cleanup function called when a thread exists to make certain that all of the
  * per-thread data is deleted.
  */
 static void thread_cleanup(void* thread_info)
 {
 	__cxa_thread_info *info = static_cast<__cxa_thread_info*>(thread_info);
 	if (info->globals.caughtExceptions)
 	{
 		// If this is a foreign exception, ask it to clean itself up.
 		if (info->foreign_exception_state != __cxa_thread_info::none)
 		{
 			_Unwind_Exception *e = reinterpret_cast<_Unwind_Exception*>(info->globals.caughtExceptions);
 			if (e->exception_cleanup)
 				e->exception_cleanup(_URC_FOREIGN_EXCEPTION_CAUGHT, e);
 		}
 		else
 		{
 			free_exception_list(info->globals.caughtExceptions);
 		}
 	}
 	free(thread_info);
 }
 
 
 /**
  * Once control used to protect the key creation.
  */
 static pthread_once_t once_control = PTHREAD_ONCE_INIT;
 
 /**
  * We may not be linked against a full pthread implementation.  If we're not,
  * then we need to fake the thread-local storage by storing 'thread-local'
  * things in a global.
  */
 static bool fakeTLS;
 /**
  * Thread-local storage for a single-threaded program.
  */
 static __cxa_thread_info singleThreadInfo;
 /**
  * Initialise eh_key.
  */
 static void init_key(void)
 {
 	if ((0 == pthread_key_create) ||
 	    (0 == pthread_setspecific) ||
 	    (0 == pthread_getspecific))
 	{
 		fakeTLS = true;
 		return;
 	}
 	pthread_key_create(&eh_key, thread_cleanup);
 	pthread_setspecific(eh_key, reinterpret_cast<void *>(0x42));
 	fakeTLS = (pthread_getspecific(eh_key) != reinterpret_cast<void *>(0x42));
 	pthread_setspecific(eh_key, 0);
 }
 
 /**
  * Returns the thread info structure, creating it if it is not already created.
  */
 static __cxa_thread_info *thread_info()
 {
 	if ((0 == pthread_once) || pthread_once(&once_control, init_key))
 	{
 		fakeTLS = true;
 	}
 	if (fakeTLS) { return &singleThreadInfo; }
 	__cxa_thread_info *info = static_cast<__cxa_thread_info*>(pthread_getspecific(eh_key));
 	if (0 == info)
 	{
 		info = static_cast<__cxa_thread_info*>(calloc(1, sizeof(__cxa_thread_info)));
 		pthread_setspecific(eh_key, info);
 	}
 	return info;
 }
 /**
  * Fast version of thread_info().  May fail if thread_info() is not called on
  * this thread at least once already.
  */
 static __cxa_thread_info *thread_info_fast()
 {
 	if (fakeTLS) { return &singleThreadInfo; }
 	return static_cast<__cxa_thread_info*>(pthread_getspecific(eh_key));
 }
 /**
  * ABI function returning the __cxa_eh_globals structure.
  */
 extern "C" __cxa_eh_globals *ABI_NAMESPACE::__cxa_get_globals(void)
 {
 	return &(thread_info()->globals);
 }
 /**
  * Version of __cxa_get_globals() assuming that __cxa_get_globals() has already
  * been called at least once by this thread.
  */
 extern "C" __cxa_eh_globals *ABI_NAMESPACE::__cxa_get_globals_fast(void)
 {
 	return &(thread_info_fast()->globals);
 }
 
 /**
  * An emergency allocation reserved for when malloc fails.  This is treated as
  * 16 buffers of 1KB each.
  */
 static char emergency_buffer[16384];
 /**
  * Flag indicating whether each buffer is allocated.
  */
 static bool buffer_allocated[16];
 /**
  * Lock used to protect emergency allocation.
  */
 static pthread_mutex_t emergency_malloc_lock = PTHREAD_MUTEX_INITIALIZER;
 /**
  * Condition variable used to wait when two threads are both trying to use the
  * emergency malloc() buffer at once.
  */
 static pthread_cond_t emergency_malloc_wait = PTHREAD_COND_INITIALIZER;
 
 /**
  * Allocates size bytes from the emergency allocation mechanism, if possible.
  * This function will fail if size is over 1KB or if this thread already has 4
  * emergency buffers.  If all emergency buffers are allocated, it will sleep
  * until one becomes available.
  */
 static char *emergency_malloc(size_t size)
 {
 	if (size > 1024) { return 0; }
 
 	__cxa_thread_info *info = thread_info();
 	// Only 4 emergency buffers allowed per thread!
 	if (info->emergencyBuffersHeld > 3) { return 0; }
 
 	pthread_mutex_lock(&emergency_malloc_lock);
 	int buffer = -1;
 	while (buffer < 0)
 	{
 		// While we were sleeping on the lock, another thread might have free'd
 		// enough memory for us to use, so try the allocation again - no point
 		// using the emergency buffer if there is some real memory that we can
 		// use...
 		void *m = calloc(1, size);
 		if (0 != m)
 		{
 			pthread_mutex_unlock(&emergency_malloc_lock);
 			return static_cast<char*>(m);
 		}
 		for (int i=0 ; i<16 ; i++)
 		{
 			if (!buffer_allocated[i])
 			{
 				buffer = i;
 				buffer_allocated[i] = true;
 				break;
 			}
 		}
 		// If there still isn't a buffer available, then sleep on the condition
 		// variable.  This will be signalled when another thread releases one
 		// of the emergency buffers.
 		if (buffer < 0)
 		{
 			pthread_cond_wait(&emergency_malloc_wait, &emergency_malloc_lock);
 		}
 	}
 	pthread_mutex_unlock(&emergency_malloc_lock);
 	info->emergencyBuffersHeld++;
 	return emergency_buffer + (1024 * buffer);
 }
 
 /**
  * Frees a buffer returned by emergency_malloc().
  *
  * Note: Neither this nor emergency_malloc() is particularly efficient.  This
  * should not matter, because neither will be called in normal operation - they
  * are only used when the program runs out of memory, which should not happen
  * often.
  */
 static void emergency_malloc_free(char *ptr)
 {
 	int buffer = -1;
 	// Find the buffer corresponding to this pointer.
 	for (int i=0 ; i<16 ; i++)
 	{
 		if (ptr == static_cast<void*>(emergency_buffer + (1024 * i)))
 		{
 			buffer = i;
 			break;
 		}
 	}
 	assert(buffer >= 0 &&
 	       "Trying to free something that is not an emergency buffer!");
 	// emergency_malloc() is expected to return 0-initialized data.  We don't
 	// zero the buffer when allocating it, because the static buffers will
 	// begin life containing 0 values.
 	memset(ptr, 0, 1024);
 	// Signal the condition variable to wake up any threads that are blocking
 	// waiting for some space in the emergency buffer
 	pthread_mutex_lock(&emergency_malloc_lock);
 	// In theory, we don't need to do this with the lock held.  In practice,
 	// our array of bools will probably be updated using 32-bit or 64-bit
 	// memory operations, so this update may clobber adjacent values.
 	buffer_allocated[buffer] = false;
 	pthread_cond_signal(&emergency_malloc_wait);
 	pthread_mutex_unlock(&emergency_malloc_lock);
 }
 
 static char *alloc_or_die(size_t size)
 {
 	char *buffer = static_cast<char*>(calloc(1, size));
 
 	// If calloc() doesn't want to give us any memory, try using an emergency
 	// buffer.
 	if (0 == buffer)
 	{
 		buffer = emergency_malloc(size);
 		// This is only reached if the allocation is greater than 1KB, and
 		// anyone throwing objects that big really should know better.  
 		if (0 == buffer)
 		{
 			fprintf(stderr, "Out of memory attempting to allocate exception\n");
 			std::terminate();
 		}
 	}
 	return buffer;
 }
 static void free_exception(char *e)
 {
 	// If this allocation is within the address range of the emergency buffer,
 	// don't call free() because it was not allocated with malloc()
 	if ((e >= emergency_buffer) &&
 	    (e < (emergency_buffer + sizeof(emergency_buffer))))
 	{
 		emergency_malloc_free(e);
 	}
 	else
 	{
 		free(e);
 	}
 }
 
 /**
  * Allocates an exception structure.  Returns a pointer to the space that can
  * be used to store an object of thrown_size bytes.  This function will use an
  * emergency buffer if malloc() fails, and may block if there are no such
  * buffers available.
  */
 extern "C" void *__cxa_allocate_exception(size_t thrown_size)
 {
 	size_t size = thrown_size + sizeof(__cxa_exception);
 	char *buffer = alloc_or_die(size);
 	return buffer+sizeof(__cxa_exception);
 }
 
 extern "C" void *__cxa_allocate_dependent_exception(void)
 {
 	size_t size = sizeof(__cxa_dependent_exception);
 	char *buffer = alloc_or_die(size);
 	return buffer+sizeof(__cxa_dependent_exception);
 }
 
 /**
  * __cxa_free_exception() is called when an exception was thrown in between
  * calling __cxa_allocate_exception() and actually throwing the exception.
  * This happens when the object's copy constructor throws an exception.
  *
  * In this implementation, it is also called by __cxa_end_catch() and during
  * thread cleanup.
  */
 extern "C" void __cxa_free_exception(void *thrown_exception)
 {
 	__cxa_exception *ex = reinterpret_cast<__cxa_exception*>(thrown_exception) - 1;
 	// Free the object that was thrown, calling its destructor
 	if (0 != ex->exceptionDestructor)
 	{
 		try
 		{
 			ex->exceptionDestructor(thrown_exception);
 		}
 		catch(...)
 		{
 			// FIXME: Check that this is really what the spec says to do.
 			std::terminate();
 		}
 	}
 
 	free_exception(reinterpret_cast<char*>(ex));
 }
 
 static void releaseException(__cxa_exception *exception)
 {
 	if (isDependentException(exception->unwindHeader.exception_class))
 	{
 		__cxa_free_dependent_exception(exception+1);
 		return;
 	}
 	if (__sync_sub_and_fetch(&exception->referenceCount, 1) == 0)
 	{
 		// __cxa_free_exception() expects to be passed the thrown object,
 		// which immediately follows the exception, not the exception
 		// itself
 		__cxa_free_exception(exception+1);
 	}
 }
 
 void __cxa_free_dependent_exception(void *thrown_exception)
 {
 	__cxa_dependent_exception *ex = reinterpret_cast<__cxa_dependent_exception*>(thrown_exception) - 1;
 	assert(isDependentException(ex->unwindHeader.exception_class));
 	if (ex->primaryException)
 	{
 		releaseException(realExceptionFromException(reinterpret_cast<__cxa_exception*>(ex)));
 	}
 	free_exception(reinterpret_cast<char*>(ex));
 }
 
 /**
  * Callback function used with _Unwind_Backtrace().
  *
  * Prints a stack trace.  Used only for debugging help.
  *
  * Note: As of FreeBSD 8.1, dladd() still doesn't work properly, so this only
  * correctly prints function names from public, relocatable, symbols.
  */
 static _Unwind_Reason_Code trace(struct _Unwind_Context *context, void *c)
 {
 	Dl_info myinfo;
 	int mylookup =
 		dladdr(reinterpret_cast<void *>(__cxa_current_exception_type), &myinfo);
 	void *ip = reinterpret_cast<void*>(_Unwind_GetIP(context));
 	Dl_info info;
 	if (dladdr(ip, &info) != 0)
 	{
 		if (mylookup == 0 || strcmp(info.dli_fname, myinfo.dli_fname) != 0)
 		{
 			printf("%p:%s() in %s\n", ip, info.dli_sname, info.dli_fname);
 		}
 	}
 	return _URC_CONTINUE_UNWIND;
 }
 
 /**
  * Report a failure that occurred when attempting to throw an exception.
  *
  * If the failure happened by falling off the end of the stack without finding
  * a handler, prints a back trace before aborting.
  */
 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)
 extern "C" void *__cxa_begin_catch(void *e) throw();
 #else
 extern "C" void *__cxa_begin_catch(void *e);
 #endif
 static void report_failure(_Unwind_Reason_Code err, __cxa_exception *thrown_exception)
 {
 	switch (err)
 	{
 		default: break;
 		case _URC_FATAL_PHASE1_ERROR:
 			fprintf(stderr, "Fatal error during phase 1 unwinding\n");
 			break;
 #if !defined(__arm__) || defined(__ARM_DWARF_EH__)
 		case _URC_FATAL_PHASE2_ERROR:
 			fprintf(stderr, "Fatal error during phase 2 unwinding\n");
 			break;
 #endif
 		case _URC_END_OF_STACK:
 			__cxa_begin_catch (&(thrown_exception->unwindHeader));
  			std::terminate();
 			fprintf(stderr, "Terminating due to uncaught exception %p", 
 					static_cast<void*>(thrown_exception));
 			thrown_exception = realExceptionFromException(thrown_exception);
 			static const __class_type_info *e_ti =
 				static_cast<const __class_type_info*>(&typeid(std::exception));
 			const __class_type_info *throw_ti =
 				dynamic_cast<const __class_type_info*>(thrown_exception->exceptionType);
 			if (throw_ti)
 			{
 				std::exception *e =
 					static_cast<std::exception*>(e_ti->cast_to(static_cast<void*>(thrown_exception+1),
 							throw_ti));
 				if (e)
 				{
 					fprintf(stderr, " '%s'", e->what());
 				}
 			}
 
 			size_t bufferSize = 128;
 			char *demangled = static_cast<char*>(malloc(bufferSize));
 			const char *mangled = thrown_exception->exceptionType->name();
 			int status;
 			demangled = __cxa_demangle(mangled, demangled, &bufferSize, &status);
 			fprintf(stderr, " of type %s\n", 
 				status == 0 ? demangled : mangled);
 			if (status == 0) { free(demangled); }
 			// Print a back trace if no handler is found.
 			// TODO: Make this optional
 			_Unwind_Backtrace(trace, 0);
 
 			// Just abort. No need to call std::terminate for the second time
 			abort();
 			break;
 	}
 	std::terminate();
 }
 
 static void throw_exception(__cxa_exception *ex)
 {
 	__cxa_thread_info *info = thread_info();
 	ex->unexpectedHandler = info->unexpectedHandler;
 	if (0 == ex->unexpectedHandler)
 	{
 		ex->unexpectedHandler = unexpectedHandler;
 	}
 	ex->terminateHandler  = info->terminateHandler;
 	if (0 == ex->terminateHandler)
 	{
 		ex->terminateHandler = terminateHandler;
 	}
 	info->globals.uncaughtExceptions++;
 
 	_Unwind_Reason_Code err = _Unwind_RaiseException(&ex->unwindHeader);
 	// The _Unwind_RaiseException() function should not return, it should
 	// unwind the stack past this function.  If it does return, then something
 	// has gone wrong.
 	report_failure(err, ex);
 }
 
 
 /**
  * ABI function for throwing an exception.  Takes the object to be thrown (the
  * pointer returned by __cxa_allocate_exception()), the type info for the
  * pointee, and the destructor (if there is one) as arguments.
  */
 extern "C" void __cxa_throw(void *thrown_exception,
                             std::type_info *tinfo,
                             void(*dest)(void*))
 {
 	__cxa_exception *ex = reinterpret_cast<__cxa_exception*>(thrown_exception) - 1;
 
 	ex->referenceCount = 1;
 	ex->exceptionType = tinfo;
 	
 	ex->exceptionDestructor = dest;
 	
 	ex->unwindHeader.exception_class = exception_class;
 	ex->unwindHeader.exception_cleanup = exception_cleanup;
 
 	throw_exception(ex);
 }
 
 extern "C" void __cxa_rethrow_primary_exception(void* thrown_exception)
 {
 	if (NULL == thrown_exception) { return; }
 
 	__cxa_exception *original = exceptionFromPointer(thrown_exception);
 	__cxa_dependent_exception *ex = reinterpret_cast<__cxa_dependent_exception*>(__cxa_allocate_dependent_exception())-1;
 
 	ex->primaryException = thrown_exception;
 	__cxa_increment_exception_refcount(thrown_exception);
 
 	ex->exceptionType = original->exceptionType;
 	ex->unwindHeader.exception_class = dependent_exception_class;
 	ex->unwindHeader.exception_cleanup = dependent_exception_cleanup;
 
 	throw_exception(reinterpret_cast<__cxa_exception*>(ex));
 }
 
 extern "C" void *__cxa_current_primary_exception(void)
 {
 	__cxa_eh_globals* globals = __cxa_get_globals();
 	__cxa_exception *ex = globals->caughtExceptions;
 
 	if (0 == ex) { return NULL; }
 	ex = realExceptionFromException(ex);
 	__sync_fetch_and_add(&ex->referenceCount, 1);
 	return ex + 1;
 }
 
 extern "C" void __cxa_increment_exception_refcount(void* thrown_exception)
 {
 	if (NULL == thrown_exception) { return; }
 	__cxa_exception *ex = static_cast<__cxa_exception*>(thrown_exception) - 1;
 	if (isDependentException(ex->unwindHeader.exception_class)) { return; }
 	__sync_fetch_and_add(&ex->referenceCount, 1);
 }
 extern "C" void __cxa_decrement_exception_refcount(void* thrown_exception)
 {
 	if (NULL == thrown_exception) { return; }
 	__cxa_exception *ex = static_cast<__cxa_exception*>(thrown_exception) - 1;
 	releaseException(ex);
 }
 
 /**
  * ABI function.  Rethrows the current exception.  Does not remove the
  * exception from the stack or decrement its handler count - the compiler is
  * expected to set the landing pad for this function to the end of the catch
  * block, and then call _Unwind_Resume() to continue unwinding once
  * __cxa_end_catch() has been called and any cleanup code has been run.
  */
 extern "C" void __cxa_rethrow()
 {
 	__cxa_thread_info *ti = thread_info();
 	__cxa_eh_globals *globals = &ti->globals;
 	// Note: We don't remove this from the caught list here, because
 	// __cxa_end_catch will be called when we unwind out of the try block.  We
 	// could probably make this faster by providing an alternative rethrow
 	// function and ensuring that all cleanup code is run before calling it, so
 	// we can skip the top stack frame when unwinding.
 	__cxa_exception *ex = globals->caughtExceptions;
 
 	if (0 == ex)
 	{
 		fprintf(stderr,
 		        "Attempting to rethrow an exception that doesn't exist!\n");
 		std::terminate();
 	}
 
 	if (ti->foreign_exception_state != __cxa_thread_info::none)
 	{
 		ti->foreign_exception_state = __cxa_thread_info::rethrown;
 		_Unwind_Exception *e = reinterpret_cast<_Unwind_Exception*>(ex);
 		_Unwind_Reason_Code err = _Unwind_Resume_or_Rethrow(e);
 		report_failure(err, ex);
 		return;
 	}
 
 	assert(ex->handlerCount > 0 && "Rethrowing uncaught exception!");
 
 	// ex->handlerCount will be decremented in __cxa_end_catch in enclosing
 	// catch block
 	
 	// Make handler count negative. This will tell __cxa_end_catch that
 	// exception was rethrown and exception object should not be destroyed
 	// when handler count become zero
 	ex->handlerCount = -ex->handlerCount;
 
 	// Continue unwinding the stack with this exception.  This should unwind to
 	// the place in the caller where __cxa_end_catch() is called.  The caller
 	// will then run cleanup code and bounce the exception back with
 	// _Unwind_Resume().
 	_Unwind_Reason_Code err = _Unwind_Resume_or_Rethrow(&ex->unwindHeader);
 	report_failure(err, ex);
 }
 
 /**
  * Returns the type_info object corresponding to the filter.
  */
 static std::type_info *get_type_info_entry(_Unwind_Context *context,
                                            dwarf_eh_lsda *lsda,
                                            int filter)
 {
 	// Get the address of the record in the table.
 	dw_eh_ptr_t record = lsda->type_table - 
 		dwarf_size_of_fixed_size_field(lsda->type_table_encoding)*filter;
 	//record -= 4;
 	dw_eh_ptr_t start = record;
 	// Read the value, but it's probably an indirect reference...
 	int64_t offset = read_value(lsda->type_table_encoding, &record);
 
 	// (If the entry is 0, don't try to dereference it.  That would be bad.)
 	if (offset == 0) { return 0; }
 
 	// ...so we need to resolve it
 	return reinterpret_cast<std::type_info*>(resolve_indirect_value(context,
 			lsda->type_table_encoding, offset, start));
 }
 
 
 
 /**
  * Checks the type signature found in a handler against the type of the thrown
  * object.  If ex is 0 then it is assumed to be a foreign exception and only
  * matches cleanups.
  */
 static bool check_type_signature(__cxa_exception *ex,
                                  const std::type_info *type,
                                  void *&adjustedPtr)
 {
 	void *exception_ptr = static_cast<void*>(ex+1);
 	const std::type_info *ex_type = ex ? ex->exceptionType : 0;
 
 	bool is_ptr = ex ? ex_type->__is_pointer_p() : false;
 	if (is_ptr)
 	{
 		exception_ptr = *static_cast<void**>(exception_ptr);
 	}
 	// Always match a catchall, even with a foreign exception
 	//
 	// Note: A 0 here is a catchall, not a cleanup, so we return true to
 	// indicate that we found a catch.
 	if (0 == type)
 	{
 		if (ex)
 		{
 			adjustedPtr = exception_ptr;
 		}
 		return true;
 	}
 
 	if (0 == ex) { return false; }
 
 	// If the types are the same, no casting is needed.
 	if (*type == *ex_type)
 	{
 		adjustedPtr = exception_ptr;
 		return true;
 	}
 
 
 	if (type->__do_catch(ex_type, &exception_ptr, 1))
 	{
 		adjustedPtr = exception_ptr;
 		return true;
 	}
 
 	return false;
 }
 /**
  * Checks whether the exception matches the type specifiers in this action
  * record.  If the exception only matches cleanups, then this returns false.
  * If it matches a catch (including a catchall) then it returns true.
  *
  * The selector argument is used to return the selector that is passed in the
  * second exception register when installing the context.
  */
 static handler_type check_action_record(_Unwind_Context *context,
                                         dwarf_eh_lsda *lsda,
                                         dw_eh_ptr_t action_record,
                                         __cxa_exception *ex,
                                         unsigned long *selector,
                                         void *&adjustedPtr)
 {
 	if (!action_record) { return handler_cleanup; }
 	handler_type found = handler_none;
 	while (action_record)
 	{
 		int filter = read_sleb128(&action_record);
 		dw_eh_ptr_t action_record_offset_base = action_record;
 		int displacement = read_sleb128(&action_record);
 		action_record = displacement ? 
 			action_record_offset_base + displacement : 0;
 		// We only check handler types for C++ exceptions - foreign exceptions
 		// are only allowed for cleanups and catchalls.
 		if (filter > 0)
 		{
 			std::type_info *handler_type = get_type_info_entry(context, lsda, filter);
 			if (check_type_signature(ex, handler_type, adjustedPtr))
 			{
 				*selector = filter;
 				return handler_catch;
 			}
 		}
 		else if (filter < 0 && 0 != ex)
 		{
 			bool matched = false;
 			*selector = filter;
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 			filter++;
 			std::type_info *handler_type = get_type_info_entry(context, lsda, filter--);
 			while (handler_type)
 			{
 				if (check_type_signature(ex, handler_type, adjustedPtr))
 				{
 					matched = true;
 					break;
 				}
 				handler_type = get_type_info_entry(context, lsda, filter--);
 			}
 #else
 			unsigned char *type_index = reinterpret_cast<unsigned char*>(lsda->type_table) - filter - 1;
 			while (*type_index)
 			{
 				std::type_info *handler_type = get_type_info_entry(context, lsda, *(type_index++));
 				// If the exception spec matches a permitted throw type for
 				// this function, don't report a handler - we are allowed to
 				// propagate this exception out.
 				if (check_type_signature(ex, handler_type, adjustedPtr))
 				{
 					matched = true;
 					break;
 				}
 			}
 #endif
 			if (matched) { continue; }
 			// If we don't find an allowed exception spec, we need to install
 			// the context for this action.  The landing pad will then call the
 			// unexpected exception function.  Treat this as a catch
 			return handler_catch;
 		}
 		else if (filter == 0)
 		{
 			*selector = filter;
 			found = handler_cleanup;
 		}
 	}
 	return found;
 }
 
 static void pushCleanupException(_Unwind_Exception *exceptionObject,
                                  __cxa_exception *ex)
 {
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 	__cxa_thread_info *info = thread_info_fast();
 	if (ex)
 	{
 		ex->cleanupCount++;
 		if (ex->cleanupCount > 1)
 		{
 			assert(exceptionObject == info->currentCleanup);
 			return;
 		}
 		ex->nextCleanup = info->currentCleanup;
 	}
 	info->currentCleanup = exceptionObject;
 #endif
 }
 
 /**
  * The exception personality function.  This is referenced in the unwinding
  * DWARF metadata and is called by the unwind library for each C++ stack frame
  * containing catch or cleanup code.
  */
 extern "C"
 BEGIN_PERSONALITY_FUNCTION(__gxx_personality_v0)
 	// This personality function is for version 1 of the ABI.  If you use it
 	// with a future version of the ABI, it won't know what to do, so it
 	// reports a fatal error and give up before it breaks anything.
 	if (1 != version)
 	{
 		return _URC_FATAL_PHASE1_ERROR;
 	}
 	__cxa_exception *ex = 0;
 	__cxa_exception *realEx = 0;
 
 	// If this exception is throw by something else then we can't make any
 	// assumptions about its layout beyond the fields declared in
 	// _Unwind_Exception.
 	bool foreignException = !isCXXException(exceptionClass);
 
 	// If this isn't a foreign exception, then we have a C++ exception structure
 	if (!foreignException)
 	{
 		ex = exceptionFromPointer(exceptionObject);
 		realEx = realExceptionFromException(ex);
 	}
 
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 	unsigned char *lsda_addr =
 		static_cast<unsigned char*>(_Unwind_GetLanguageSpecificData(context));
 #else
 	unsigned char *lsda_addr =
 		reinterpret_cast<unsigned char*>(static_cast<uintptr_t>(_Unwind_GetLanguageSpecificData(context)));
 #endif
 
 	// No LSDA implies no landing pads - try the next frame
 	if (0 == lsda_addr) { return continueUnwinding(exceptionObject, context); }
 
 	// These two variables define how the exception will be handled.
 	dwarf_eh_action action = {0};
 	unsigned long selector = 0;
 	
 	// During the search phase, we do a complete lookup.  If we return
 	// _URC_HANDLER_FOUND, then the phase 2 unwind will call this function with
 	// a _UA_HANDLER_FRAME action, telling us to install the handler frame.  If
 	// we return _URC_CONTINUE_UNWIND, we may be called again later with a
 	// _UA_CLEANUP_PHASE action for this frame.
 	//
 	// The point of the two-stage unwind allows us to entirely avoid any stack
 	// unwinding if there is no handler.  If there are just cleanups found,
 	// then we can just panic call an abort function.
 	//
 	// Matching a handler is much more expensive than matching a cleanup,
 	// because we don't need to bother doing type comparisons (or looking at
 	// the type table at all) for a cleanup.  This means that there is no need
 	// to cache the result of finding a cleanup, because it's (quite) quick to
 	// look it up again from the action table.
 	if (actions & _UA_SEARCH_PHASE)
 	{
 		struct dwarf_eh_lsda lsda = parse_lsda(context, lsda_addr);
 
 		if (!dwarf_eh_find_callsite(context, &lsda, &action))
 		{
 			// EH range not found. This happens if exception is thrown and not
 			// caught inside a cleanup (destructor).  We should call
 			// terminate() in this case.  The catchTemp (landing pad) field of
 			// exception object will contain null when personality function is
 			// called with _UA_HANDLER_FRAME action for phase 2 unwinding.  
 			return _URC_HANDLER_FOUND;
 		}
 
 		handler_type found_handler = check_action_record(context, &lsda,
 				action.action_record, realEx, &selector, ex->adjustedPtr);
 		// If there's no action record, we've only found a cleanup, so keep
 		// searching for something real
 		if (found_handler == handler_catch)
 		{
 			// Cache the results for the phase 2 unwind, if we found a handler
 			// and this is not a foreign exception.
 			if (ex)
 			{
 				saveLandingPad(context, exceptionObject, ex, selector, action.landing_pad);
 				ex->languageSpecificData = reinterpret_cast<const char*>(lsda_addr);
 				ex->actionRecord = reinterpret_cast<const char*>(action.action_record);
 				// ex->adjustedPtr is set when finding the action record.
 			}
 			return _URC_HANDLER_FOUND;
 		}
 		return continueUnwinding(exceptionObject, context);
 	}
 
 
 	// If this is a foreign exception, we didn't have anywhere to cache the
 	// lookup stuff, so we need to do it again.  If this is either a forced
 	// unwind, a foreign exception, or a cleanup, then we just install the
 	// context for a cleanup.
 	if (!(actions & _UA_HANDLER_FRAME))
 	{
 		// cleanup
 		struct dwarf_eh_lsda lsda = parse_lsda(context, lsda_addr);
 		dwarf_eh_find_callsite(context, &lsda, &action);
 		if (0 == action.landing_pad) { return continueUnwinding(exceptionObject, context); }
 		handler_type found_handler = check_action_record(context, &lsda,
 				action.action_record, realEx, &selector, ex->adjustedPtr);
 		// Ignore handlers this time.
 		if (found_handler != handler_cleanup) { return continueUnwinding(exceptionObject, context); }
 		pushCleanupException(exceptionObject, ex);
 	}
 	else if (foreignException)
 	{
 		struct dwarf_eh_lsda lsda = parse_lsda(context, lsda_addr);
 		dwarf_eh_find_callsite(context, &lsda, &action);
 		check_action_record(context, &lsda, action.action_record, realEx,
 				&selector, ex->adjustedPtr);
 	}
 	else if (ex->catchTemp == 0)
 	{
 		// Uncaught exception in cleanup, calling terminate
 		std::terminate();
 	}
 	else
 	{
 		// Restore the saved info if we saved some last time.
 		loadLandingPad(context, exceptionObject, ex, &selector, &action.landing_pad);
 		ex->catchTemp = 0;
 		ex->handlerSwitchValue = 0;
 	}
 
 
 	_Unwind_SetIP(context, reinterpret_cast<unsigned long>(action.landing_pad));
 	_Unwind_SetGR(context, __builtin_eh_return_data_regno(0),
 	              reinterpret_cast<unsigned long>(exceptionObject));
 	_Unwind_SetGR(context, __builtin_eh_return_data_regno(1), selector);
 
 	return _URC_INSTALL_CONTEXT;
 }
 
 /**
  * ABI function called when entering a catch statement.  The argument is the
  * pointer passed out of the personality function.  This is always the start of
  * the _Unwind_Exception object.  The return value for this function is the
  * pointer to the caught exception, which is either the adjusted pointer (for
  * C++ exceptions) of the unadjusted pointer (for foreign exceptions).
  */
 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)
 extern "C" void *__cxa_begin_catch(void *e) throw()
 #else
 extern "C" void *__cxa_begin_catch(void *e)
 #endif
 {
 	// We can't call the fast version here, because if the first exception that
 	// we see is a foreign exception then we won't have called it yet.
 	__cxa_thread_info *ti = thread_info();
 	__cxa_eh_globals *globals = &ti->globals;
 	globals->uncaughtExceptions--;
 	_Unwind_Exception *exceptionObject = static_cast<_Unwind_Exception*>(e);
 
 	if (isCXXException(exceptionObject->exception_class))
 	{
 		__cxa_exception *ex =  exceptionFromPointer(exceptionObject);
 
 		if (ex->handlerCount == 0)
 		{
 			// Add this to the front of the list of exceptions being handled
 			// and increment its handler count so that it won't be deleted
 			// prematurely.
 			ex->nextException = globals->caughtExceptions;
 			globals->caughtExceptions = ex;
 		}
 
 		if (ex->handlerCount < 0)
 		{
 			// Rethrown exception is catched before end of catch block.
 			// Clear the rethrow flag (make value positive) - we are allowed
 			// to delete this exception at the end of the catch block, as long
 			// as it isn't thrown again later.
 			
 			// Code pattern:
 			//
 			// try {
 			//     throw x;
 			// }
 			// catch() {
 			//     try {
 			//         throw;
 			//     }
 			//     catch() {
 			//         __cxa_begin_catch() <- we are here
 			//     }
 			// }
 			ex->handlerCount = -ex->handlerCount + 1;
 		}
 		else
 		{
 			ex->handlerCount++;
 		}
 		ti->foreign_exception_state = __cxa_thread_info::none;
 		
 		return ex->adjustedPtr;
 	}
 	else
 	{
 		// If this is a foreign exception, then we need to be able to
 		// store it.  We can't chain foreign exceptions, so we give up
 		// if there are already some outstanding ones.
 		if (globals->caughtExceptions != 0)
 		{
 			std::terminate();
 		}
 		globals->caughtExceptions = reinterpret_cast<__cxa_exception*>(exceptionObject);
 		ti->foreign_exception_state = __cxa_thread_info::caught;
 	}
 	// exceptionObject is the pointer to the _Unwind_Exception within the
 	// __cxa_exception.  The throw object is after this
 	return (reinterpret_cast<char*>(exceptionObject) + sizeof(_Unwind_Exception));
 }
 
 
 
 /**
  * ABI function called when exiting a catch block.  This will free the current
  * exception if it is no longer referenced in other catch blocks.
  */
 extern "C" void __cxa_end_catch()
 {
 	// We can call the fast version here because the slow version is called in
 	// __cxa_throw(), which must have been called before we end a catch block
 	__cxa_thread_info *ti = thread_info_fast();
 	__cxa_eh_globals *globals = &ti->globals;
 	__cxa_exception *ex = globals->caughtExceptions;
 
 	assert(0 != ex && "Ending catch when no exception is on the stack!");
 	
 	if (ti->foreign_exception_state != __cxa_thread_info::none)
 	{
 		if (ti->foreign_exception_state != __cxa_thread_info::rethrown)
 		{
 			_Unwind_Exception *e = reinterpret_cast<_Unwind_Exception*>(ti->globals.caughtExceptions);
 			if (e->exception_cleanup)
 				e->exception_cleanup(_URC_FOREIGN_EXCEPTION_CAUGHT, e);
 		}
 		globals->caughtExceptions = 0;
 		ti->foreign_exception_state = __cxa_thread_info::none;
 		return;
 	}
 
 	bool deleteException = true;
 
 	if (ex->handlerCount < 0)
 	{
 		// exception was rethrown. Exception should not be deleted even if
 		// handlerCount become zero.
 		// Code pattern:
 		// try {
 		//     throw x;
 		// }
 		// catch() {
 		//     {
 		//         throw;
 		//     }
 		//     cleanup {
 		//         __cxa_end_catch();   <- we are here
 		//     }
 		// }
 		//
 		
 		ex->handlerCount++;
 		deleteException = false;
 	}
 	else
 	{
 		ex->handlerCount--;
 	}
 
 	if (ex->handlerCount == 0)
 	{
 		globals->caughtExceptions = ex->nextException;
 		if (deleteException)
 		{
 			releaseException(ex);
 		}
 	}
 }
 
 /**
  * ABI function.  Returns the type of the current exception.
  */
 extern "C" std::type_info *__cxa_current_exception_type()
 {
 	__cxa_eh_globals *globals = __cxa_get_globals();
 	__cxa_exception *ex = globals->caughtExceptions;
 	return ex ? ex->exceptionType : 0;
 }
 
 /**
  * ABI function, called when an exception specification is violated.
  *
  * This function does not return.
  */
 extern "C" void __cxa_call_unexpected(void*exception) 
 {
 	_Unwind_Exception *exceptionObject = static_cast<_Unwind_Exception*>(exception);
 	if (exceptionObject->exception_class == exception_class)
 	{
 		__cxa_exception *ex =  exceptionFromPointer(exceptionObject);
 		if (ex->unexpectedHandler)
 		{
 			ex->unexpectedHandler();
 			// Should not be reached.  
 			abort();
 		}
 	}
 	std::unexpected();
 	// Should not be reached.  
 	abort();
 }
 
 /**
  * ABI function, returns the adjusted pointer to the exception object.
  */
 extern "C" void *__cxa_get_exception_ptr(void *exceptionObject)
 {
 	return exceptionFromPointer(exceptionObject)->adjustedPtr;
 }
 
 /**
  * As an extension, we provide the ability for the unexpected and terminate
  * handlers to be thread-local.  We default to the standards-compliant
  * behaviour where they are global.
  */
 static bool thread_local_handlers = false;
 
 
 namespace pathscale
 {
 	/**
 	 * Sets whether unexpected and terminate handlers should be thread-local.
 	 */
 	void set_use_thread_local_handlers(bool flag) throw()
 	{
 		thread_local_handlers = flag;
 	}
 	/**
 	 * Sets a thread-local unexpected handler.  
 	 */
 	unexpected_handler set_unexpected(unexpected_handler f) throw()
 	{
 		static __cxa_thread_info *info = thread_info();
 		unexpected_handler old = info->unexpectedHandler;
 		info->unexpectedHandler = f;
 		return old;
 	}
 	/**
 	 * Sets a thread-local terminate handler.  
 	 */
 	terminate_handler set_terminate(terminate_handler f) throw()
 	{
 		static __cxa_thread_info *info = thread_info();
 		terminate_handler old = info->terminateHandler;
 		info->terminateHandler = f;
 		return old;
 	}
 }
 
 namespace std
 {
 	/**
 	 * Sets the function that will be called when an exception specification is
 	 * violated.
 	 */
 	unexpected_handler set_unexpected(unexpected_handler f) throw()
 	{
 		if (thread_local_handlers) { return pathscale::set_unexpected(f); }
 
 		return ATOMIC_SWAP(&unexpectedHandler, f);
 	}
 	/**
 	 * Sets the function that is called to terminate the program.
 	 */
 	terminate_handler set_terminate(terminate_handler f) throw()
 	{
 		if (thread_local_handlers) { return pathscale::set_terminate(f); }
 
 		return ATOMIC_SWAP(&terminateHandler, f);
 	}
 	/**
 	 * Terminates the program, calling a custom terminate implementation if
 	 * required.
 	 */
 	void terminate()
 	{
 		static __cxa_thread_info *info = thread_info();
 		if (0 != info && 0 != info->terminateHandler)
 		{
 			info->terminateHandler();
 			// Should not be reached - a terminate handler is not expected to
 			// return.
 			abort();
 		}
 		terminateHandler();
 	}
 	/**
 	 * Called when an unexpected exception is encountered (i.e. an exception
 	 * violates an exception specification).  This calls abort() unless a
 	 * custom handler has been set..
 	 */
 	void unexpected()
 	{
 		static __cxa_thread_info *info = thread_info();
 		if (0 != info && 0 != info->unexpectedHandler)
 		{
 			info->unexpectedHandler();
 			// Should not be reached - a terminate handler is not expected to
 			// return.
 			abort();
 		}
 		unexpectedHandler();
 	}
 	/**
 	 * Returns whether there are any exceptions currently being thrown that
 	 * have not been caught.  This can occur inside a nested catch statement.
 	 */
 	bool uncaught_exception() throw()
 	{
 		__cxa_thread_info *info = thread_info();
 		return info->globals.uncaughtExceptions != 0;
 	}
 	/**
 	 * Returns the number of exceptions currently being thrown that have not
 	 * been caught.  This can occur inside a nested catch statement.
 	 */
 	int uncaught_exceptions() throw()
 	{
 		__cxa_thread_info *info = thread_info();
 		return info->globals.uncaughtExceptions;
 	}
 	/**
 	 * Returns the current unexpected handler.
 	 */
 	unexpected_handler get_unexpected() throw()
 	{
 		__cxa_thread_info *info = thread_info();
 		if (info->unexpectedHandler)
 		{
 			return info->unexpectedHandler;
 		}
 		return ATOMIC_LOAD(&unexpectedHandler);
 	}
 	/**
 	 * Returns the current terminate handler.
 	 */
 	terminate_handler get_terminate() throw()
 	{
 		__cxa_thread_info *info = thread_info();
 		if (info->terminateHandler)
 		{
 			return info->terminateHandler;
 		}
 		return ATOMIC_LOAD(&terminateHandler);
 	}
 }
 #if defined(__arm__) && !defined(__ARM_DWARF_EH__)
 extern "C" _Unwind_Exception *__cxa_get_cleanup(void)
 {
 	__cxa_thread_info *info = thread_info_fast();
 	_Unwind_Exception *exceptionObject = info->currentCleanup;
 	if (isCXXException(exceptionObject->exception_class))
 	{
 		__cxa_exception *ex =  exceptionFromPointer(exceptionObject);
 		ex->cleanupCount--;
 		if (ex->cleanupCount == 0)
 		{
 			info->currentCleanup = ex->nextCleanup;
 			ex->nextCleanup = 0;
 		}
 	}
 	else
 	{
 		info->currentCleanup = 0;
 	}
 	return exceptionObject;
 }
 
 asm (
 ".pushsection .text.__cxa_end_cleanup    \n"
 ".global __cxa_end_cleanup               \n"
 ".type __cxa_end_cleanup, \"function\"   \n"
 "__cxa_end_cleanup:                      \n"
 "	push {r1, r2, r3, r4}                \n"
 "	bl __cxa_get_cleanup                 \n"
 "	push {r1, r2, r3, r4}                \n"
 "	b _Unwind_Resume                     \n"
 "	bl abort                             \n"
 ".popsection                             \n"
 );
 #endif